In order to increase the dynamic range for Analog-to-Digital Converters, a technique known as "gain ranging" has been utilized. This technique requires two data conversion paths, each path having a different amplification associated therewith. A threshold detector determines the signal level on the input and then defines the signal path that is to be utilized. If it is below a defined low signal level threshold, the high gain path is utilized, and if it is above a predetermined high signal level threshold, the high gain path is utilized. If the signal level is detected as being between the two thresholds, then a "blending" of the two signals can be facilitated.
One disadvantage to the above-noted gain ranging technique is that, when the two digital signals are combined in the blending operation, it is important to ensure that the two paths have the same magnitude, phase and DC off-set characteristics. The DC off-set can be removed with a high pass filter in each path. However, any remaining mismatch due to gain or phase mismatch can result in audible distortion. It is this gain mismatch and phase mismatch that must be corrected for in order to ensure that the combining of the two digital outputs is achieved correctly to prevent such distortion.